Process of waterproofing fibrous material



Patented Dec. 5, 1939 PATENT OFFICE PROCESS OF WATERPROOFING FIBROUS MATERIAL I Edward B. Bell, Lowell, Mass., assignor to Hall tion of Pennsylvania Laboratories, Inc., Pittsburgh, Pa., a corpora- No Drawing. ApplicationJuly 12, 1937,

' Serial No. 153,293

10 Claims.

This invention relates to a process of waterproofing fibrous material, and more particularly to a process of waterproofing leather.

The invention is applicable to the waterproof- 5 ing of vegetable or animal fibers which in their raw or in their manufactured condition have the disadvantage of absorbing moisture. By the present invention, such materials may be made substantiallytimpervious to water with freedom 10 from shrinking, cracking or change of color. The

invention is particularly applicable to waterproofing leather fibers and will be described as applied to the treatment of leather, it being unr derstood, however, that it may be employed in treating other animal or vegetable fibrous material. Leather is especially susceptible to harm by contact with Water, resulting in cracking and shrinking of the leather. It also causes loss of color and strength in the leather.

20 The following is a specific example of a process of Waterproofing leather according to the present invention. The leather to be waterproofed is immersed in a solution of sodium hexametaphosphate, alum, soap and ammonia at a tempera- 25 ture of approximately 120 F. After soaking for a short time, the leather is removed and dried preferably at moderate temperature. For waterproofing 5 grams of leather the following quantities of alum, sodium oleate, sodium hexameta- 30 phosphate and ammonia may be dissolved in 50 ml. of water:

. Grams Alum. 0.053 Sodium oleate 2.750 [35 Sodium hexametaphosphate 2.500 Ammonia 2.500

The leather is soaked in this bath for several minutes at a temperature of 120 F., the solution squeezed out, and the leather dried at a moderate temperature. The drying temperature should not be above that which will. harm the leather and may be any temperature higher than that which will cause evaporation of the ammonia. As a result of this treatment, the leather is waterproofed without afiecting its color, feel, odor or strength of the fiber.

The alum and sodium oleate react to form aluminum soap which is kept in solution-by the .5 combination of the ammonia and the sodium hexametaphosphate. The leather which has been soaked in this solution, upon drying, liberates the ammonia which causes the deposition of aluminum soap throughout the fibers of the 5 leather.

Instead of employing alum, I may use salts of other metals, such as lead or tin or other amphoteric metals which do not form complexes with the ammonia or with other solvents which may be employed in place of ammonia. The pre- 5 ferred metal used in forming the metallic soap is aluminum.

In place of ammonia, I may use other alkaline materials which are solvents for metallic soaps and which evaporate at temperatures which will not harm the leather or other fibrous material which is being waterproofed. Examples of such other alkaline solvents for metallic soaps are triethanolamine or diethanolamine.

. In place of sodium oleate, I may other suitable fatty acid soap.

I may employ other phosphates instead of sodium hexametaphosphate, commonly known as Grahams salt. I may employ the alkali-metal pyrophosphates or tripolyphosphates, for example sodium pyrophosphate (NarPzOv) or sodium tripolyphosphate (NasPzOio). The alkalimetal metaphosphates, tripolyphosphates and pyrophosphates may be considered as molecularly dehydrated phosphates since they may be formed from alkali-metal orthophosphates by dehydrating the orthophosphates so as to effect an atomic re-arrangement within the phosphate molecule. These molecularly dehydrated phosphates may be considered as derived from phosphoric acid containing less water than orthophosphoric acid. The term molecularly dehydrated alkali-metal phosphate as used in the claims is intended to include the alkali-metal metaphosphates, tripolyphosphates or pyrophosphates. Any of these phosphates may be employed in conjunction with the ammonia or other solvent for dissolving the metallic soap.

Textile fibers, such for example as wool, silk, cotton or linen, or paper fibers may be treated either before or after fabrication with the waterproofing solution and the solvent evaporated to impregnate the fibers with the metallic soap.

employ any 15 The invention is not limited to the example given or to the specific materials mentioned, but may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. A process of waterproofing fibrous material, which comprises treating it with a solution of a salt of an amphoteric metal, a water-soluble soap, an alkaline solvent for the metallic soap, said solvent evaporating at a temperature which will not harm the material being treated, and a molecularly dehydrated alkali-metal phosphate. and evaporating the solvent to deposit the metallic soap.

2. A process of waterproofing fibrous material,

which comprises treating it with a solution of a salt of an amphoteric metal, a water-soluble soap, ammonia and Grahams salt, and evaporating the solvent to deposit the metallic soap. 5. A process of Waterproofing fibrous material, which comprises treating it with a solution of a salt of an amphoteric metal, a water-soluble soap, ammonia and an alkali-metal pyrophosphate, and evaporating the solvent to deposit the metallic soap.

6. A process of waterproofing fibrous material, which comprises treating it with a solution of a salt of an amphoteric metal, a water-soluble soap, ammonia and an alkali-metal tripolyphosphate, and evaporating the solvent to deposit the metallic soap.

7.- A process of waterproofing fibrous material, which comprises treating it with a solution of an aluminum salt, a water-soluble soap, ammonia and a molecularly dehydrated alkali-metal phosphate, and evaporating the ammonia to deposit the metallic soap.

8. A process'of waterproofing leather, which comprises treating it with a solution of a salt of an amphoteric metal, a water-soluble soap, ammonia and a molecularly dehydrated alkalimetal phosphate, and evaporating the ammonia to deposit the metallic soap.-

9. A process of waterproofing leather, which comprises treating it with a solution of an aluminum salt, a water-soluble soapgammonia and a molecularly dehydrated alkali-metal phosphate, and evaporating theammonia to deposit the me? tallic soap. j

10. A process of waterproofing leather, which water-soluble soap, ammonia and a molecularly dehydrated alkali-metal phosphate, and evaporating the ammonia to deposit the'metallic soap.

DWARD B. BELL.

comprises treating it with a solution'of alum, 

